Database.PostgreSQL.Store.RowParser

Row parser

data RowParser w a

Consumes w columns of a result set row in order to produce an instance of a.

Instances

Functor (RowParser w)

Methods

fmap :: (a -> b) -> RowParser w a -> RowParser w b

(<$) :: a -> RowParser w b -> RowParser w a

data RowErrorLocation

Location of an error

Constructors

RowErrorLocation Column Row

Instances

Eq RowErrorLocation

Methods

(==) :: RowErrorLocation -> RowErrorLocation -> Bool

(/=) :: RowErrorLocation -> RowErrorLocation -> Bool

Ord RowErrorLocation

Methods

compare :: RowErrorLocation -> RowErrorLocation -> Ordering

(<) :: RowErrorLocation -> RowErrorLocation -> Bool

(<=) :: RowErrorLocation -> RowErrorLocation -> Bool

(>) :: RowErrorLocation -> RowErrorLocation -> Bool

(>=) :: RowErrorLocation -> RowErrorLocation -> Bool

max :: RowErrorLocation -> RowErrorLocation -> RowErrorLocation

min :: RowErrorLocation -> RowErrorLocation -> RowErrorLocation

Show RowErrorLocation

Methods

showsPrec :: Int -> RowErrorLocation -> ShowS

show :: RowErrorLocation -> String

showList :: [RowErrorLocation] -> ShowS

data RowErrorDetail

Errors that occur during row parsing

Constructors

TooFewColumns

Underlying RowParser wants more columns than are currently present.

ColumnRejected

A column value could not be parsed.

Instances

Eq RowErrorDetail

Methods

(==) :: RowErrorDetail -> RowErrorDetail -> Bool

(/=) :: RowErrorDetail -> RowErrorDetail -> Bool

Ord RowErrorDetail

Methods

compare :: RowErrorDetail -> RowErrorDetail -> Ordering

(<) :: RowErrorDetail -> RowErrorDetail -> Bool

(<=) :: RowErrorDetail -> RowErrorDetail -> Bool

(>) :: RowErrorDetail -> RowErrorDetail -> Bool

(>=) :: RowErrorDetail -> RowErrorDetail -> Bool

max :: RowErrorDetail -> RowErrorDetail -> RowErrorDetail

min :: RowErrorDetail -> RowErrorDetail -> RowErrorDetail

Show RowErrorDetail

Methods

showsPrec :: Int -> RowErrorDetail -> ShowS

show :: RowErrorDetail -> String

showList :: [RowErrorDetail] -> ShowS

data RowError

An error that occured when parsing a row

Constructors

RowError RowErrorLocation RowErrorDetail

Instances

Eq RowError

Methods

(==) :: RowError -> RowError -> Bool

(/=) :: RowError -> RowError -> Bool

Ord RowError

Methods

compare :: RowError -> RowError -> Ordering

(<) :: RowError -> RowError -> Bool

(<=) :: RowError -> RowError -> Bool

(>) :: RowError -> RowError -> Bool

(>=) :: RowError -> RowError -> Bool

max :: RowError -> RowError -> RowError

min :: RowError -> RowError -> RowError

Show RowError

Methods

showsPrec :: Int -> RowError -> ShowS

show :: RowError -> String

showList :: [RowError] -> ShowS

processResultWith :: forall a n. KnownNat n => Result -> RowParser n a -> ExceptT RowError IO [a]

Process the each row of the Result with the given RowParser.

Means of composition

(>>=$) :: forall a v b w. KnownNat v => RowParser v a -> (a -> RowParser w b) -> RowParser (v + w) b infixl 1

Transform the result of another RowParser. Similar to monadic bind. Also keeps track of how many columns are needed in total.

(>>$) :: forall a v b w. KnownNat v => RowParser v a -> RowParser w b -> RowParser (v + w) b infixl 1

Chain two RowParsers, but discard the result of the first.

(<*>$) :: forall a v b w. KnownNat v => RowParser v (a -> b) -> RowParser w a -> RowParser (v + w) b infixl 4

Just like the '(*)' operator.

finish :: a -> RowParser 0 a

Terminate the parsing tree by returning the final result.

cancel :: RowErrorDetail -> RowParser 0 a

Terminate the parsing tree with an error.

skipColumns :: RowParser n ()

Skip a number of columns.

nonNullCheck :: Int -> RowParser 0 Bool

Check if the following n columns are not NULL.

Default parsers

processContent :: (Oid -> Maybe ByteString -> Maybe a) -> RowParser 1 a

Process the contents of a column.

retrieveColumn :: RowParser 1 (Oid, Maybe ByteString)

Retrieve a column's type and content.

retrieveContent :: RowParser 1 ByteString

Retrieve a column's content.